[Objective]Under the increasing penetration of renewable energy, the coordinated operation of interconnected multi-microgrids faces the challenge of simultaneously improving economic efficiency, reducing carbon-emission-related costs, and mitigating load fluctuations. Existing dispatch methods generally treat electricity-price and carbon-cost signals as predetermined parameters, and the interaction among internal settlement prices, carbon-cost signals, and inter-microgrid power transactions is insufficiently considered. To address these issues, a coordinated low-carbon dispatch method for multi-microgrids under electricity-carbon market coupling is proposed. 

[Methods]An interconnected multi-microgrid system consisting of three heterogeneous microgrids is established, incorporating wind power, photovoltaic generation, conventional generating units, energy storage systems, demand response, main-grid power exchange, and inter-microgrid power exchange. The 24-hour internal settlement electricity price and carbon-emission cost guidance coefficient are jointly optimized as decision variables. A discount-based pricing mechanism is introduced for inter-microgrid electricity transactions based on the internal settlement electricity price, thereby establishing a price linkage between internal power exchange and electricity trading with the main grid. On this basis, a coordinated low-carbon dispatch model is formulated by considering conventional-unit output, energy-storage charging and discharging, demand response, main-grid power exchange, inter-microgrid power exchange, and the corresponding operational constraints. An improved water flow optimization (IWFO) algorithm is developed to search for the electricity-carbon signal combinations. The algorithm incorporates opposition-based learning initialization, Lévy-flight-enhanced turbulence, a gravitational sinking-flow mechanism, and a Cauchy-Gaussian hybrid stagnation-escape strategy. For each candidate electricity-carbon signal combination, the corresponding multi-microgrid dispatch scheme is solved, and the comprehensive operating performance of the system is used to update the search process, thereby realizing the coordinated optimization of electricity-carbon signals and dispatch strategies. 

[Results]The case-study results show that the dynamic electricity-carbon signals can promote the coordinated participation of energy storage, demand response, and inter-microgrid power exchange. Compared with the fixed electricity-carbon signal case, the total operating cost decreases from CNY 3,904.3 to CNY 3,808.7, representing a reduction of approximately 2.4%. The carbon-emission-related cost decreases by 10.7%, while the peak-to-valley load difference decreases by 18.2%. The results further show that joint optimization of the internal settlement electricity price and carbon-emission cost guidance coefficient provides more effective comprehensive regulation than optimization of either signal alone. Benchmark-function tests and ablation experiments also demonstrate the improved optimization performance of IWFO. 

[Conclusion]The proposed method establishes a coordinated interaction among internal electricity-price signals, carbon-cost guidance, and multi-microgrid operating decisions. By coordinating conventional generation, energy storage, demand response, and inter-microgrid power exchange, the proposed approach promotes temporal and spatial complementarity among heterogeneous microgrids and improves the overall coordination among economic operation, carbon-emission-related cost control, and load regulation.